Anisotropic depth velocity model estimation above the receiver array in walkaway or 3D VSP data

摘要

A walkaway VSP survey is carried out using a receiver array. Using a vertical VSP survey and arrival times of surface multiples on the walkaway VSP, vertical interval velocities and the anisotropy parameters δ and ε are estimated. This may then be used to process surface seismic data to do a prestack depth migration of surface seismic data and used for interpretation. For multi-azimuthal walkaway or 3D VSP data, we deterinine two VTI parameters ε and δ for multi-azimuth vertical planes. Then we determine five anisotropic interval parameters that describe P- wave kinematics for orthorhombic layers. These orthorhombic parameters may then be used to process surface seismic data to give a stacked image in true depth and for the interpretation purposes.